498 A. j. jukes-browne's supplementary 



doubt of this identity ; those from the Perte du Rhone which retain 

 the shell agree entirely with Mr. Seeley's type, which has the shell 

 converted into phosphate of lime, and is preserved in Mr. Carter's 

 collection. 



D'Orbigny's figure does not express the rugose lamellae under- 

 neath, which coexist with the striae said to be characteristic ; the 

 nodules also are made too regular and too distinctly double, whereas 

 they are only elongated or bilobed. 



Mr. Seeley's figure of the under surface is very good ; but the 

 side view gives too high an elevation, and the base is badly drawn ; 

 the nodulations, again, are too distinctly single ; on the specimen 

 itself they are more irregular, more elongate, and may have been 

 bilobate. The side view of this and also of a Rhone specimen are 

 given in PI. XXII. figs. 3 & 5. 



Those from the Perte du Rhone vary much in height, some having 

 the elevation of T. nodosa, others being low and resembling that 

 called T. eoopansa by Mr. Seeley. One individual of the Cambridge 

 T. expansa shows protuberances on the cast caused by the tuber- 

 culations of the shell : they are probably only varieties of the same 

 species. 



Trochus cancellatus, Seeley. 



Comp. Turbo indecisus, D'Orb. Pal. Fr. p. 230. 



I think MM. Pictet and Campiche must have been mistaken in 

 referring any Cambridge specimens to T. Tollotianus. I have recently 

 had an opportunity of comparing them with specimens from the 

 Perte du Rhone ; and though these are somewhat similar to T. 

 cancelled us in shape, yet they are quite smooth, showing neither 

 spiral lines nor cancellated markings ; neither is there any trace of 

 the occasional varices. 



I am inclined to think therefore that Trochus cancellatus is a 

 distinct species, and that T. ToHoticums does not exist in the 

 Cambridge Greensand. I may mention that it was by a mistake 

 that the latter name was inserted in the Explanation of plate xiv. 

 appended to my former paper (Quart. Journ. Geol. Soc. vol. xxxi. 

 p. 313). 



[Since writing the above I have seen the collection of D'Orbigny's 

 types at the Jardin des Plantes in Paris : and among these I found 

 specimens named Turbo indecisus, which appear identical with T. 

 cancellatus ; one of them shows the longitudinal markings, and 

 another the full cancellations, in the same variable way as the Cam- 

 bridge casts exhibit them. D'Orbigny, p. 230, says that it occurs 

 at Eocragnoles, Perte du Rhone, and Clansaye, but that he only 

 knew the internal cast.] 



Natica levistriata, new sp. PI. XXI. fig. 6. 



Shell globose ; spire moderately high : whorls flattened above, so 

 as to produce a slight angulation which runs round the spire : below 

 this on the body- whorl there are 10 or 11 slightly elevated spiral 

 striae. The angulation may be otherwise described as the highest 



